Protein adhesives containing dicyanimide compounds as fluidizing agents



Patented Jan. 1, 1952 i UNITED STATES PATENT FHZE PROTEIN ADHESIVES CONTAINING DI- CYANIIVHDE CO AGENT$ R UND AS LUID Z- Chester G. .Landes, New ..-Ganaan, and John tu enr, Stamford. O ca :Qyanam d {lump corporation of 'Maine No Drawing. Anplication september zz, 1 948,

*SerialNo.-'5Q,657

a water-soluble or wateredispersiblealkali metal or .ammoniumsalt, the ,most common being casein and vegetable proteins such a corn protein .(zein), wheat protein vggladin), barley protein ,(hordein), andsoya protein, the principal .constituent of which is glycinin. ,Qrdinarily the 1 protein ,isdispersed in ,a water solution of the solubilizing alkali, with or without the aid nf organic solvents such as ethanol or dispersing agents such as rosi-nsoapsand the like, and the resulting dispersions are employed directly as liquid adhesives or sizes.

Aqueous alkaline pr otein dispersion which :are employed as adhesives ,usually contain from about 10% to 35% of solids of which the protein comprises the major portion. Where the dispersions are to be employed as sizing compositions, the content of protein solids usually .is from 1% to 10% of the weight of the dispersions. Similarly, in coating compositionsfor incorporating fillers inpaper, textiles, etc., from 1% to about 1 5% of protein is present in the coating mixture.

On the other hand, casein and soya proteins have been used extensively in the preparation of dry adhesive mixes. In these compositions the protein material "is dry mixed with varying proportions of alkaline agents which .aid ;in dispersing or solubilizing the vprotein "in water. Such alkaline agents as sodium hydroxide, potassium hydroxide, ammonium hydroxide, and similar alkaline agents consisting of monovalent ions are commonly employed for this purpose. Also includedin the dry adhesive mix is an alkali icontaining .a polyvalent metal such as, for example, calcium hydroxide. The heavy metal alkaline material serves to precipitate the protein from :solution or dispersion and imparts to the adhesive, when dispersed in water, relatively quick setting properties.

Heretoiore, .variousdisadvantagesfliaveiattend- (CI- El 46) east? use cirreteisadh s vss I th us o 19- his pro e he it be n im acticab 5 adhesives. :For this reah s be n thecuswm t p epa n aque- -ine protein --adhe sive containing ,i-rom i01 p otsmand s as t e somnosi e a st ck-iv pa tim i0 ave e w st throus isel a th irr .e hr ein s z n gc mpetiti nsecsn ais sssasei .set

V 1p emit m aa is e a :b n .i ses iblw obtai timer-. erties n oatings containing more it asst-ti.

, qtein ,cqsmzed isasanrpbl aw 2 alwa dant n weuseiefatlsetronic substance The ease of brush, knife or rgil application of e r-seem 1 af resta e a1 up c l mi t e emmsr ial y ac en e bas n t at he v ;1s hi n i nqte coatin mpositions ..necessit t d the -.;.ev poraticn zzlarse amounts at water .fnom the coa ed materials, thus adding materially to tire-poster coated 1-.paner-.and:texti1es.

:Inrzregardvtorthe :dry protein. ;adhesiveanixes,.zit has heretofore heenZ-impracticable to employ aqueouszdispersionsrthereof containing. morethan -abonts% ofrprotein due .to the quick setting characteristicssimparted .=thereto by the polyvalent metal alkaline materials, and the :short working lifeot these adhesives :has been-a major :disadvanta'ge in the use-thereof.

We havediscoveredthat-protein -adhesives*ma y -be --rendered less viscous in aqueous dispersion and may be stabilized against premature gelling by the addition thereto oismallamounts-of alkali 'metaland ammoniumsalts of dicyani-mide. Representative members of this group o'f'eo npeunds include sodium dicyanimide, potassium dicyani- :mide,--and-ammoniumdicyanimide. All of these compounds-are -'so'l-id, watersoluble ;rnateriails,

h h e'a so u l "i aq eou milk. "prets n and-'soya protein dispersions, and the-compounds are also stable in aqueous alkaline solution. It

will be noted that since the members of our preerredg-roup' 20f fluidifying :agents aresolid maiterialsnthey :may sbevadded to :theiordinary l-iquid -protein--adhesives .or they may be admixed in dry condition with protein adhesive compositions.

The amounts of our fluidifying agents which may be satisfactorily employed are within the range of from about 5% to about 20-30% based on the weight of the. particular dry proteinaceous compound used. Greater amounts of the fluidifying agents may be employed if desired although for commercial practicability amounts greater than about 30% of the agents will not ordinarily be used.

Our invention, in its broadest aspect, comprises the preparation of protein adhesive compositions which are characterized by initial viscosities, when in aqueous condition, which are much lower than the viscosities of similar adhesives heretofore employed in the art. The improved fluidity and stability of the novel protein adhesives are obtained by the presence therein of from about 5% to about 20-30% of any of the above-described fluidifying agents. Our novel fiuidiiying agents may be added to the dry milk protein or soya protein adhesive compositions by simply dry-mixing the components of the mix. The dry composition may be stored indefinitely without deterioration and may thereafter be dispersed in water and applied according to well known procedures. The presence of alkali metal and ammonium salts of dicyanimide does not interfere with the precipitating action of heavy metal bases present in the dry protein adhesives, but our novel fluidifying agents extend the working life of such adhesives by virtue of the fact that they decrease the initial viscosity of such adhesives when they are employed in liquid condition. On the other hand, our novel fluidifying agents may equally as well be added to aqueous protein adhesive compositions which may thereafter be employed accordin to known methods, and the treated liquid adhesives are rendered fluid stable by such addition.

The primary advantage to be derived from the present invention resides in the fact that our improved protein adhesive compositions remain fluid and usable in aqueous condition for exceptionally long periods of time. Those compositions of relatively low protein content, such as 5-10%, are stabilized against thickening, while the rate of gelation is greatly reduced in adhesives having a higher content of protein, such as -40% or more. 7

Another advantage of the present invention is that the presence of our novel fluidifying agents in the adhesive compositions permits the preparation of aqueous adhesives containing up to about 35-40% of protein in contrast to the previous upper commercial limit of about -30% of protein.

A further advantage of our invention is that, due to the fact that all of our novel fiuidifying agents are solid, water-soluble compositions, it is possible to prepare dry milk protein and soya protein adhesive compositions which may be stored indefinitely and which, when dispersed in water, remain fluid and usable for long periods of time. i l

The followin examples are presented to more fully explain our invention. The examples are given primarily for illustrative purposes and other embodiments of the invention may be employed within the scope of the appended claims.

Example 1 Ten grams of sodium dicyanimide were dissolved in 283 grams of water and 107 gramsof commercial casein (94.44% casein) were added to the solution. After soaking for about 15 minutes; 14 grams of armnonium hydroxide (28.42% NI-Ia) were added, after which the dispersion was heated with stirring on a water bath to 93 F. The so-obtained liquid casein adhesive contained approximately 25% of casein solids. The product had an initial Brookfield viscosity of 14,200 centipoises at 30 R. P. M. After aging for 24 hours at 72 F., the adhesive composition had a viscosity of 76,400 centipoises. and after 10 days aging the adhesive was still pourable. A control sample which was similarly prepared but which contained no fiuidifying agent had an initial viscosity greater than 100,000 centipoises and gelled upon agin for 24 hours at 72 F.

Example 2 The procedure of Example 1 was repeated except that 20 grams of ammonium dicyanimide were substituted for the sodium dicyanimide. The product obtained had an initial viscosity of 38,000 centipoises, and the sample remained fluid for 10. days.

Example 3 scribed mix was added, respectively, 1.4 grams of sodium dicyanimide and 1.4 grams of ammonium dicyanimide, and each of these dry mixes was dispersed in 45 grams of water. The'sample containing the sodium dicyanimide had an initial Brookfield viscosity of 2,600, while the sample containing the ammonium dicyanimide had an initial viscosity of 5,220 centipoises.

Example 4 The procedure of Example 3 was repeated except that 4.2 grams of sodium dicyanimide was employed instead of 1.4 grams thereof. The initial viscosity of the sample was 7,800 centipoises.

Example 5 Sixty grams of alpha protein (a soya protein) were soaked in 240 grams of water for 15 minutes. Thereafter, 40 grams of water containing 7.8 grams of sodium carbonate, 1.8 grams of borax,

' and 6 grams of sodium dicyanimide were added to the aqueous protein dispersion. The mixture was then heated at F. for 15 minutes.

A control sample was prepared similarly to the above-described sample except that no fluidifying agent was employed. Both samples were tested with a Brookfield viscosimeter at 6 R. P. M. for initial viscosity and viscosity after standing for 19 hours. Test results were as follows:

From the foregoing description it will be seen that the present invention affords protein adhesives which have greatly reduced viscosities in aqueous condition and which remain fluid and usable for longer periods of time. The aqueous adhesives may be employed according to accepted methods, as by tub or calender application, roll, brush, or knife coaters, or by other known methods with the advantages described above. Inasmuch as the initial viscosities of our novel adhesive compositions are extremely low, the content of protein which may be employed may be much greater than that which it has previously been possible to employ. Similarly, since the novel protein adhesive compositions of the invention are fluid stable, waste of protein material is thus minimized, afiording a long needed advantage over the prior art commercial adhesives containing casein, wheat protein, soya protein, barley protein, zein, and the like proteinaceous materials.

What We claim is:

1. An aqueous adhesive composition consisting essentially of about 5 to per cent by weight of an alkali-solubilized protein dispersed in about 95 to 65 per cent of water together with from 5 to 30 per cent, based on the dry weight of said protein, of a member selected from the group consisting of ammonium and alkali metal salts dicyanimide.

2. An aqueous adhesive composition consisting essentially of about 5 to 35 per cent by weight of an alkali-solubilized casein dispersed in about 95 to 65 per cent of water together with from 5 to 30 per cent, based on the dry weight of said casein, of a member selected from the group consisting of ammonium and alkali metal salts of dicyanimide.

3. A dry composition suitable for dispersion in water to form an adhesive composition containing up to about 40% of protein comprising essentially a mixture of casein, a water-soluble alkali in amount sufiicient to solubilize said casein, and a fluidifying amount within the range of from 5 to 30 per cent, based on the dry weight of the casein, of a member selected from the group consisting of ammonium and alkali metal salts of dicyanimide.

4. An aqueous adhesive composition consisting essentially of about 5 to 35 per cent by weight of an alkali-solubilized soya protein dispersed in about 95 to 65 per cent of water together with from 5 to 30 per cent, based on the dry weight of said soya protein, of a member selected from the group consisting of ammonium and alkali metal salts of dicyanimide.

5. A dry composition suitable for dispersion in water to form an adhesive composition containing up to about 40% of protein comprising essentially a mixture of soya protein, a water-soluble alkali in amount sufficient to solubilize said soya protein, and a fluidifying amount within the range of from 5 to 30 per cent, based on the dry weight of the soya protein, of a member selected from the group consisting of ammonium and alkali metal salts of dicyanimide.

6. A dry composition suitable for dispersion in water to form an adhesive composition containing up to about 40% of protein comprising casein having admixed therewith a suificient quantity of a water-soluble alkali to solubilize said casein and a fluidifying amount within the range of from 5 to 30 per cent, based on the dry weight of the casein, of sodium dicyanimide.

7. A dry composition suitable for dispersion in water to form an adhesive composition containing up to about 40% of protein comprising casein from 5 to 30 per cent, based on the dry weight of the casein, of potassium dicyanimide 9. A dry composition suitable for dispersion in water to form an adhesive composition containing up to about 40% of protein comprising soya protein having admixed therewith a sufficient quantity of a water-soluble alkali to solubilize said soya protein, and a fluidifying amount within the range of from 5 to 30 per cent, based on the dry Weight of the soya protein, of sodium dicyanimide.

10. A dry composition suitable for dispersion in water to form an adhesive composition containing up to about 40% of protein comprising soya protein having admixed therewith a suificient quantity of a water-soluble alkali to solubilize said soya protein, and a fiuidifying amount within the range of from 5 to 30 per cent, based on the dry weight of the soya protein, of ammonium dicyanimide.

11. A dry composition suitable for dispersion in water to form an adhesive composition containing up to about 40% of protein comprising soya protein having admixed therewith a sufiicient quantity of a water-soluble alkali to solubilize said soya protein, and a fiuidifying amount within the range of from 5 to 30 per cent, based on the dry weight of the soya protein, of potassium dicyanimide. I

CHESTER G. LANDES. JOHN STUDENY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Australia Sept. 3, 1942 

1. AN AQUEOUS ADHESIVE COMPOSITION CONSISTING ESSENTIALLY OF ABOUT 5 TO 35 PER CENT BY WEIGHT OF AN ALKALI-SOLUBILIZED PROTEIN DISPERSED IN ABOUT 95 TO 65 PER CENT OF WATER TOGETHER WITH FROM 5 TO 30 PER CENT, BASED ON THE DRY WEIGHT OF SAID PROTEIN, OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF AMMONIUM AND ALKALI METAL SALTS OF DICYANIMIDE. 